Study On Hydrological Response Of Climate And Land Use Change In Mahe River Basin

The research aimed to establish SWAT distributed hydrologic model and analyze influence of the climatic change and land use change on runoff in Ma River basin. Through collection and actual investigation methods obtained DEM, land use and soil data of basin. Simultaneously, through processing the collected data to establish the input database of SWAT model.In which, daily flow rate in Cua Dat station in1999was used to calibrate model parameter, and daily flow rate in2005was used to verify. The SWAT model was used to simulate the hydrological process of Ma River basin. After calibration and verification, the related coefficient exceed0.8, Nash coefficient exceed0.7, which showed a good simulated result in runoff simulation by SWAT.Based on the forecast of IPCC and actual measurement data from nearly30years of Ma River basin reflect the trend of climate change. Setting2kinds of climate change scenarios (A2and B2scenarios), SWAT model was used to simulate influence of the future climatic change on runoff in Ma River basin. Climate evolution by the trend of both scenarios of A2and B2is all to cause the harder impact for the extreme phenomena in the21st century. This climate change is making the flow of flood peak to be able to maximum increase up to about20%(A2scenario, August), while the flow in the driest month can reduce about27%(A2scenario, April).Based on the spatial distribution characteristic of basin topography, slope and soil and population growth, economic development requirement. Effects of land use change on hydrological cycle in watershed is quantitatively analyzed using3land use scenarios. The results show that runoff, evapotranspiration, percolation and water yield are sensitive to the land use change. The extreme changes of land use are only to cause small changes for the year runoff, but it causes the hard change of runoff by the season. With the appropriate development plans of land use are capable to reduce flood in the flood season and severity of drought in the dry season. Simultaneously, it improves the economic situation and sustainable development in the basin.The evaluated combination scenario showed that it reduced year runoff (reduce from1.3%-1.4%). Simultaneously, it reduced the runoff in the flood season (reduce from2%-26%) and increased the runoff in the dry season (increase up from11%-48%). This means that combination is capable to overcome the extreme changes due to the caused climate change and land use. Finally, from the perspective of water resources management debate the hydrological response to climate change and land use change. The research could provide reference basis for water resource management in Ma River basin.